Skip to contents
bslib 0.5.0.9000
  • Get Started
    Shiny dashboards Any Bootstrap project Theming
  • Theming
    Theming variables Utility Classes Custom components
  • Components
    Cards Sidebars Value Boxes
  • Layouts
    Multiple columns Multiple panels Filling layout
  • Reference
  • News

Cards

Source: vignettes/cards.Rmd
cards.Rmd

Cards are a common organizing unit for modern user interfaces (UI). At their core, they’re just rectangular containers with borders and padding. However, when utilized properly to group related information, they help users better digest, engage, and navigate through content. This is why most successful dashboard/UI frameworks make cards a core feature of their component library. This article provides an overview of the API that bslib provides to create Bootstrap cards.

Setup code

To demonstrate that bslib cards work outside of Shiny (i.e., in R Markdown, static HTML, etc), we’ll make repeated use of statically rendered htmlwidgets like plotly and leaflet. Here’s some code to create those widgets:

library(bslib)
library(shiny)
library(htmltools)
library(plotly)
library(leaflet)

plotly_widget <- plot_ly(x = diamonds$cut) %>%
  config(displayModeBar = FALSE) %>%
  layout(margin = list(t = 0, b = 0, l = 0, r = 0))

leaflet_widget <- leafletOptions(attributionControl = FALSE) %>%
  leaflet(options = .) %>%
  addTiles()

Shiny usage

Cards work equally well in Shiny. In the examples below, replace plotly_widget with plotlyOutput() and leaflet_widget with leafletOutput() to adapt them for Shiny server-rendered plots/maps.

Hello card()

A card() is designed to handle any number of “known” card items (e.g., card_header(), card_body(), etc) as unnamed arguments (i.e., children). As we’ll see shortly, card() also has some useful named arguments (e.g., full_screen, height, etc).

At their core, card() and card items are just an HTML div() with a special Bootstrap class, so you can use Bootstrap’s utility classes to customize things like colors, text, borders, etc.

card(
  card_header(
    class = "bg-dark",
    "A header"
  ),
  card_body(
    markdown("Some text with a [link](https://github.com)")
  )
)
A header

Some text with a link

Implicit card_body()

If you find yourself using card_body() without changing any of its defaults, consider dropping it altogether since any direct children of card() that aren’t “known” card() items, are wrapped together into an implicit card_body() call.1 For example, the code to the right generates HTML that is identical to the previous example:

card(
  card_header(
    class = "bg-dark",
    "A header"
  ),
  markdown("Some text with a [link](https://github.com).")
)
A header

Some text with a link.

Restricting growth

By default, a card()’s size grows to accommodate the size of it’s contents. Thus, if a card_body() contains a large amount of text, tables, etc., you may want to specify a height or max_height. That said, when laying out multiple cards, it’s likely best not to specify height on the card(), and instead, let the layout determine the height layout_column_wrap().

Although scrolling is convenient for reducing the amount of space required to park lots of content, it can also be a nuisance to the user. To help reduce the need for scrolling, consider pairing scrolling with full_screen = TRUE (which adds an icon to expand the card’s size to the browser window). Notice how, when the card is expanded to full-screen, max_height/height won’t effect the full-screen size of the card.

card(
  max_height = 250,
  full_screen = TRUE,
  card_header(
    "A long, scrolling, description"
  ),
  lorem::ipsum(paragraphs = 3, sentences = 5)
)
A long, scrolling, description

Adipiscing tellus dignissim libero interdum: tortor dictum, commodo tellus sem – imperdiet pellentesque cubilia! Fames ante ac id et ultricies vehicula accumsan. Posuere natoque nascetur habitant nunc libero parturient dictumst, auctor ligula sed! Vivamus pellentesque turpis habitant potenti rutrum enim non ridiculus. Integer malesuada suscipit, dictumst et auctor viverra posuere penatibus facilisi.

Elit enim ad dignissim nibh conubia varius tempor? Integer tincidunt curabitur non blandit porta sodales nostra mus? Mus molestie consequat phasellus penatibus. Sapien sagittis curabitur lacinia, facilisis, lobortis nisl lacinia parturient. Habitasse elementum maecenas himenaeos urna magnis ultricies; vulputate luctus, platea eget taciti nulla aliquet aliquet purus ante augue.

Elit hac lobortis ante, sociosqu mattis vitae; penatibus suscipit sodales sodales? Lobortis arcu conubia, metus ridiculus natoque turpis duis phasellus! Cursus suspendisse integer dictum litora ridiculus donec, odio rutrum? Tortor hac bibendum quisque, porttitor ultricies, aenean convallis. Id erat sapien cum, et congue dapibus, platea ultricies mattis arcu.

Expand

Filling outputs

A card()’s default behavior is optimized for facilitating filling layouts. More specifically, if a fill item (e.g., plotly_widget), appears as a direct child of a card_body(), it resizes to fit the card()s specified height. This means, by specifying height = 250 we’ve effectively shrunk the plot’s height from its default of 400 down to about 200 pixels. And, when expanded to full_screen, the plot grows to match the card()’s new size.

card(
  height = 250,
  full_screen = TRUE,
  card_header("A filling plot"),
  card_body(plotly_widget)
)
A filling plot
Expand

Most htmlwidgets (e.g., plotly, leaflet, etc) and some other Shiny output bindings (e.g, plotOutput(), imageOutput(), etc) are fill items by default, so this behavior “just works” in those scenarios. And, in some of these situations, it’s helpful to remove card_body()’s padding, which can be done via spacing & alignment utility classes.

card(
  height = 275,
  full_screen = TRUE,
  card_header("A filling map"),
  card_body(
    class = "p-0",
    leaflet_widget
  ),
  card_footer(
    class = "fs-6",
    "Copyright 2023 RStudio, PBC"
  )
)
A filling map
Copyright 2023 RStudio, PBC
Expand

Fill item(s) aren’t limited in how much they grow and shrink, which can be problematic when a card becomes very small. To work around this, consider adding a min_height on the card_body() container. For example, try using the handle on the lower-right portion of this card example to make the card taller/smaller.

This interactive example is a bit contrived in that we’re using CSS resize to demonstrate how to make plots that don’t shrink beyond a certain point, but this concept becomes quite useful when implementing page-level filling layouts (i.e., page_fillable()) with multiple cards.

card(
  height = 300,
  style = "resize:vertical;",
  card_header("Plots that grow but don't shrink"),
  card_body(
    min_height = 250,
    plotly_widget,
    plotly_widget
  )
)
Plots that grow but don't shrink

Troubleshooting fill

As you’ll learn more about in filling layouts, a fill item loses its ability to fill when wrapped in additional UI element that isn’t a fillable container. To fix the situation, use as_fill_carrier() to allow the additional element to carry the potential to fill from the card_body() down to the fill item.

Multiple card_body()

A card() can have multiple card_body()s, which is especially useful for:

  1. Combining both resizable and non-resizable contents (i.e., fill items and non-fill).
  2. Allowing each card_body() to have their own styling (via inline styles and/or utility classes) and resizing limits (e.g., min_height).

For example, when pairing filling output with scrolling content, you may want min_height on the filling output since the scrolling content will force it to shrink:

card(
  height = 375,
  full_screen = TRUE,
  card_header(
    "Filling plot, scrolling description"
  ),
  card_body(
    min_height = 200,
    plotly_widget
  ),
  card_body(
    class = "lead container",
    lorem::ipsum(paragraphs = 10, sentences = 5)
  )
)
Filling plot, scrolling description

Amet netus conubia posuere, nostra, venenatis commodo nibh nisl aptent primis tempus. Nisl habitasse viverra, montes, posuere hendrerit fringilla volutpat! Molestie tellus pharetra dignissim vulputate risus arcu, platea hendrerit eleifend. At vehicula nulla litora, ligula per libero aliquet: congue per imperdiet? Nulla penatibus lectus velit lectus luctus nisl tellus vestibulum orci ligula!

Ipsum eros ridiculus et suspendisse augue fermentum. Proin erat aliquam donec netus vestibulum nostra inceptos tellus. Gravida nascetur sodales neque nisl conubia risus platea id. Suscipit turpis tortor dictumst arcu facilisi pharetra orci lacinia nec cras dictumst donec mi. Parturient vestibulum quis potenti mollis.

Dolor arcu egestas auctor, lobortis lacinia mollis aliquet duis dignissim. Montes sociosqu iaculis porttitor blandit, hac fames fermentum accumsan. Congue sodales euismod, urna vulputate, mattis ullamcorper cursus mauris, parturient netus placerat! Dis cras porta commodo vitae feugiat nascetur. Congue quis class consequat, cras euismod justo tristique aliquam molestie.

Ipsum iaculis diam facilisis congue sapien, dignissim fringilla. Varius convallis blandit elementum viverra ligula, montes nascetur mi vehicula? Vulputate hac tincidunt aliquam – gravida nostra, sagittis eget hendrerit, dui senectus tempus aliquet? Mauris hac cursus morbi sagittis senectus sociis pulvinar purus quam aliquam faucibus porttitor. Na porttitor.

Amet ultricies sollicitudin interdum netus sapien, vel tellus suscipit suspendisse class sapien. Hendrerit est arcu, eleifend: bibendum phasellus parturient habitasse velit justo. Nisi facilisi cubilia magnis, dis volutpat nibh quis senectus facilisi tincidunt cursus ad arcu. Iaculis pharetra purus ullamcorper sapien ante suscipit a. Congue.

Sit gravida himenaeos pulvinar sem ridiculus class nascetur, quam nunc. Lacinia convallis, vivamus posuere malesuada euismod pretium scelerisque litora. Praesent sodales gravida – vivamus purus; vitae vivamus purus massa. Congue at sociosqu porttitor magna lacinia interdum quis laoreet enim. Ullamcorper torquent felis dui nisl diam eros pellentesque?

Amet hendrerit, quisque aenean auctor penatibus tincidunt ultrices. Dignissim justo, nunc vestibulum nascetur sed suspendisse nulla in feugiat? Himenaeos purus natoque donec nisi sollicitudin ut felis est fringilla? Tempus elementum conubia nisi, pharetra taciti in turpis. Hac turpis non tincidunt magnis nascetur vitae, eu nisl, litora diam ultrices, dis laoreet eros mollis.

Dolor justo magnis at inceptos ridiculus dis sed condimentum; vehicula nostra. Nec non conubia dapibus taciti; a ad orci! Sociosqu molestie ultrices semper placerat, ultricies – porttitor duis aliquam diam purus. Interdum euismod cras, magna duis nec inceptos curae leo cum dis. Consequat tortor tincidunt torquent blandit quisque tristique et – pellentesque magna: dignissim eros ultrices ultrices nunc!

Adipiscing ut natoque – sociis ac magna convallis faucibus ornare etiam mattis. Aenean auctor felis odio sociosqu senectus. Mattis quam ultrices augue vestibulum mus quam in – quam cursus? Pretium pretium sodales ridiculus cras euismod. Odio curabitur quam est mauris, facilisis etiam pulvinar eleifend odio lacus, senectus commodo vitae mauris; nascetur venenatis rutrum blandit.

Lorem parturient nostra scelerisque habitasse neque nunc, quis fringilla? Orci nec vel; vestibulum posuere curae metus malesuada suscipit netus facilisi. Sagittis sagittis vulputate nec aliquet sociis ultrices dis pharetra lectus neque volutpat. Ultrices lacus convallis neque tincidunt arcu suscipit curabitur. Erat habitasse risus nibh id torquent iaculis, nulla montes fringilla ligula.

Expand

Also, when the content has a fixed size, and should not be allowed to scroll, set fill = FALSE:

card(
  height = 350,
  full_screen = TRUE,
  card_header(
    "Filling plot, short description"
  ),
  plotly_widget,
  card_body(
    fill = FALSE,
    card_title("A subtitle"),
    p(class = "text-muted", "And a caption")
  )
)
Filling plot, short description
A subtitle

And a caption

Expand

Multiple columns

As you’ll learn in column-based layouts, layout_column_wrap() is great for multi-column layouts that are responsive and accommodate for filling output. Here we have an equal-width 2-column layout using width = 1/2, but it’s also possible to have varying column widths.

card(
  height = 350,
  full_screen = TRUE,
  card_header("A multi-column filling layout"),
  card_body(
    min_height = 200,
    layout_column_wrap(
      width = 1/2,
      plotOutput("p1"),
      plotOutput("p2")
    )
  ),
  lorem::ipsum(paragraphs = 3, sentences = 5)
)
A multi-column filling layout

Amet imperdiet dis tellus suspendisse, sociis aptent eleifend. Viverra non iaculis ac platea eu nisl. Torquent volutpat penatibus cras, placerat semper aenean class morbi ullamcorper. Eros platea, est vulputate vestibulum a nulla, egestas morbi? Curabitur nullam sollicitudin sem orci, taciti placerat, donec sollicitudin torquent velit curabitur purus augue?

Adipiscing elementum sed netus facilisi ut suscipit, vestibulum imperdiet, hendrerit gravida platea? Dictum praesent arcu elementum dictum fusce id. Praesent lectus, vestibulum aliquam donec turpis sagittis. Rhoncus massa scelerisque, et, primis magnis massa faucibus donec blandit libero diam. Duis at tellus curabitur hendrerit nullam vivamus egestas diam primis nulla, pretium cubilia nunc.

Adipiscing ultricies nec urna egestas nascetur – leo: sapien sapien non leo! Commodo inceptos netus litora et sapien semper faucibus justo felis eleifend rhoncus tempor. Sed praesent suspendisse, at tempor auctor lectus commodo. Felis in in interdum habitasse odio ut aptent suscipit leo erat sed? Sem nascetur placerat mattis venenatis morbi ligula himenaeos; magnis montes praesent integer mauris lacus.

Expand

Multiple cards

layout_column_wrap() is especially nice for laying out multiple cards since each card in a particular row will have the same height (by default). Learn more in column-based layouts.

layout_column_wrap(
  width = 1/2,
  height = 300,
  card(full_screen = TRUE, card_header("A filling plot"), plotly_widget),
  card(full_screen = TRUE, card_header("A filling map"), card_body(class = "p-0", leaflet_widget))
)
A filling plot
Expand
A filling map
Expand

Multiple tabs

navset_card_tab() and navset_card_pill() make it possible to create cards with multiple tabs or pills. These functions have the same full_screen capabilities as normal card()s as well some other options like title (since there is no natural place for a card_header() to be used). Note that, each nav_panel() object is similar to a card(). That is, if the direct children aren’t already card items (e.g., card_title()), they get implicitly wrapped in a card_body().

library(leaflet)
navset_card_tab(
  height = 450,
  full_screen = TRUE,
  title = "HTML Widgets",
  nav_panel(
    "Plotly",
    card_title("A plotly plot"),
    plotly_widget
  ),
  nav_panel(
    "Leaflet",
    card_title("A leaflet plot"),
    leaflet_widget
  ),
  nav_panel(
    shiny::icon("circle-info"),
    markdown("Learn more about [htmlwidgets](http://www.htmlwidgets.org/)")
  )
)
HTML Widgets
  • Plotly
  • Leaflet
A plotly plot
A leaflet plot

Learn more about htmlwidgets

Expand

Sidebars

As you’ll learn more about in sidebar layouts, layout_sidebar() just works when placed inside in a card(). In this case, if you want fill items (e.g., plotly_widget) to still fill the card like we’ve seen before, you’ll need to set fillable = TRUE in layout_sidebar().

card(
  height = 300,
  full_screen = TRUE,
  card_header("A sidebar layout inside a card"),
  layout_sidebar(
    fillable = TRUE,
    sidebar = sidebar(
      actionButton("btn", "A button")
    ),
    plotly_widget
  )
)
A sidebar layout inside a card
Expand

Static images

card_image() makes it easy to embed static (i.e., pre-generated) images into a card. Provide a URL to href to make it clickable. In the case of multiple card_image()s, consider laying them out in multiple cards with layout_column_wrap() to produce a grid of clickable thumbnails.

card(
  height = 300,
  full_screen = TRUE,
  card_image(
    file = "shiny-hex.svg",
    href = "https://github.com/rstudio/shiny"
  ),
  card_body(
    fill = FALSE,
    card_title("Shiny for R"),
    p(
      class = "fw-light text-muted",
      "Brought to you by RStudio."
    )
  )
)
Shiny for R

Brought to you by RStudio.

Expand

Flexbox

Both card() and card_body() default to fillable = TRUE (that is, they are CSS flexbox containers), which works wonders for facilitating filling outputs, but it also leads to surprising behavior with inline tags (e.g., actionButton(), span(), strings, etc). Specifically, each inline tag is placed on a new line, but in a “normal” layout flow (fillable = FALSE), inline tags render inline.

card(
  card_body(
    fillable = TRUE,
    "Here's some", tags$i("inline"), "text",
    actionButton("btn1", "A button")
  ),
  card_body(
    fillable = FALSE,
    "Here's some", tags$i("inline"), "text",
    actionButton("btn2", "A button")
  )
)
Here's some inline text
Here's some inline text

That said, sometimes working in a flexbox layout is quite useful, even when working with inline tags. Here we leverage flexbox’s gap property to control the spacing between a plot, a (full-width) button, and paragraph. Note that, by using markdown() for the paragraph, it wraps the results in a <p> tag, which means the contents of the paragraph are not longer subject to flexbox layout. If we wanted, we could do something similar to render the actionButton() inline by wrapping it in a div().

card(
  height = 325, full_screen = TRUE,
  card_header("A plot with an action links"),
  card_body(
    class = "gap-2 container",
    plotly_widget,
    actionButton(
      "go_btn", "Action button",
      class = "btn-primary rounded-0"
    ),
    markdown("Here's a _simple_ [hyperlink](https://www.google.com/).")
  )
)
A plot with an action links

Here's a simple hyperlink.

Expand

In addition to gap, flexbox has really nice ways of handling otherwise difficult spacing and alignment issues. And, thanks to Bootstrap’s flex utility classes, we can easily opt-in and customize defaults.

card(
  height = 300, full_screen = TRUE,
  card_header(
    class = "d-flex justify-content-between",
    "Centered plot",
    checkboxInput("check", " Check me", TRUE)
  ),
  card_body(
    class = "align-items-center",
    plotOutput("id", width = "75%")
  )
)
Centered plot
Expand

Shiny

Since this article is statically rendered, the examples here use statically rendered content/widgets, but the same card() functionality works for dynamically rendered content via Shiny (e.g., plotOutput(), plotlyOutput(), etc).

An additional benefit that comes with using shiny is the ability to use getCurrentOutputInfo() to render new/different content when the output container becomes large enough, which is particularly useful with card(full_screen = T, ...). For example, you may want additional captions/labels when a plot is large, additional controls on a table, etc (see the value boxes article for a clever use of this).

# UI logic
ui <- page_fluid(
  card(
    max_height = 200,
    full_screen = TRUE,
    card_header("A dynamically rendered plot"),
    plotOutput("plot_id")
  )
)

# Server logic
server <- function(input, output, session) {
  output$plot_id <- renderPlot({
    info <- getCurrentOutputInfo()
    if (info$height() > 600) {
      # code for "large" plot
    } else {
      # code for "small" plot
    }
  })
}

shinyApp(ui, server)

Appendix

The following CSS is used to give plotOutput() a background color; it’s necessary here because this documentation page is not actually hooked up to a Shiny app, so we can’t show a real plot.

.shiny-plot-output {
  background-color: #216B7288;
  height: 400px;
  width: 100%;
}

On this page

Developed by Carson Sievert, Joe Cheng, Garrick Aden-Buie, Posit Software, PBC.

Site built with pkgdown 2.0.7.